1. Field of the Invention
The present invention relates to a display device which has a plurality of pixels arranged in matrix, and to an electronic apparatus using the display device. More specifically, the invention relates to a display device which controls each pixel by inputting a video signal to a selected pixel and displays an image, and to an electronic apparatus using the display device.
2. Description of the Related Art
Demand for a dot matrix display device such as a liquid crystal display device has rapidly increased not only for stationary applications such as a TV receiver and a display for a personal computer but also for mobile applications. In recent years, an EL display device which has a pixel including an organic electroluminescence element (hereinafter referred to as an organic EL) has started to be put into practical use as a next generation display device substituted for the liquid crystal display device.
In general, a dot matrix display device has a passive matrix type and an active matrix type. There are an analog grayscale method and a digital grayscale method as a method for achieving grayscale in an active matrix display device. In the analog grayscale method, grayscale is achieved by controlling the luminance of a pixel. In the digital grayscale method, each pixel is controlled by two values depending on whether light is emitted or not. The grayscale is achieved in accordance with the size of a light emitting area or the length of a light emitting time in a certain period. The former is called an area grayscale method and the latter is called a time grayscale method.
In the aforementioned time grayscale method, one frame period is divided into a plurality of subframe periods to weight the light emitting time in each subframe period. Then, in accordance with a combination of the subframe periods, luminance per one frame period is controlled to achieve grayscale. Patent Documents 1 and 2 disclose one of the methods for achieving multi-grayscale in this manner.
[Patent Document 1] Japanese Patent Laid-Open Publication No. 2001-5426
[Patent Document 2] Japanese Patent Laid-Open Publication No. 2001-324958